In the analysis of biological specimens, the specimens are often stained with one or more combinations of stains or assays, and the stained biological specimen is viewed or imaged for further analysis. Observing the assay enables a variety of processes, including diagnosis of disease, assessment of response to treatment, and development of new drugs to fight disease.
Multiplex staining is a technique for the detection of multiple biomarkers within a single tissue section and has become more popular due to its significant efficiencies and the rich diagnostic information it generates. Immunohistochemical (IHC) slide staining can be utilized to identify proteins, protein fragments, or nucleic acids in cells of a tissue section and hence is widely used in the study of different types of cells, such as cancerous cells and immune cells in biological tissue. In the context of staining for immune cells, the immunological data indicates the type, density, and location of the immune cells within tumor samples and this data is of particular interest to pathologists in determining a patient survival prediction. Thus, IHC staining may be used in research to understand the distribution and localization of the differentially expressed biomarkers of immune cells (such as T-cells or B-cells) in a cancerous tissue for an immune response study. For example, tumors often contain infiltrates of immune cells, which may prevent the development of tumors or favor the outgrowth of tumors. In this context, multiple stains are used to target different types of immune cells, and the population distribution of each type of immune cell is used in studying the clinical outcome of the patients.
Typically, in immunoscore computations, a medical professional uses a multiplex assay that involves staining one piece of tissue or a simplex assay that involves staining adjacent serial tissue sections to detect or quantify markers, for example, multiple proteins or nucleic acids etc., in the same tissue block. With the stained slides available, the immunological data, for instance, the type, density and location of the immune cells, can be estimated from the tumor tissue samples.
In the traditional workflow for immunoscore computation, the expert reader selects the representative fields of view (FOVs) or regions of interest (ROIs) manually, as the initial step, by reviewing the slide under a microscope or reading an image of a slide, which has been scanned/digitized, on a display. When the tissue slide is scanned, the scanned image is viewed by independent readers and the FOVs or ROIs are manually marked based on the readers' personal preferences. After selecting the FOVs or ROIs, a pathologist/reader manually counts the immune cells within the selected FOVs or ROIs. Manual selection of the FOVs or ROIs and counting is highly subjective and biased to the readers, as different readers may select different FOVs or ROIs to count. Hence, an immunoscore study is not necessarily reproducible.